Nah, I call bullshit on that. The same language issues would apply for an offline game, and as for ISP issues - that's something for Sony to sort out, not individual publishers.
Fact is, PS2 Online just isn't big enough in Europe. Ironically, the very thing that makes PS2 outsell Xbox (it's mass market appeal) is the very thing holding it back in the online sector. Mainstream casual gamers just don't have much interest in online gaming - it's seen as too much hassle and too much added expense. Xbox LIVE does better because it's a gamers console, designed for online play from the start, and it's owners are more likely to be comfortable with, and interested in, online gaming.
Also, sales for Resident Evil titles have been dipping since Nemesis. Gun Survivor only came out in the UK via one chain of specialist shops. My gut feeling is that Capcom see Outbreak as a similarly niche title.